Video graphic adapters (VGA) are used to render video signals to be rasterized on display devices such as computer monitors. In operation, VGAs will generally receive graphics information from a system, such as a computer system, and perform the necessary graphics calculations upon the received information in order to render graphics signals. Once all calculations have been performed upon an object during image rendering, the data representing the object to be rasterized is written into a frame buffer. During image rendering, the graphics calculations are repeated for all objects associated with a specific frame, and data are stored within the frame buffer. During rasterization, the image is read from the frame buffer to create a video signal that is provided to the display device. During image rendering, the graphics calculations are repeated for all objects associated with a specific frame, and data are stored within the frame buffer. The playback of video motion, as opposed to the display of a still or paused image, requires rendering, rasterizing and displaying video information relatively quickly.
Although LCD-type displays are commonly used, LCD-type displays typically have relatively slow response times especially when displaying motion video. Therefore, LCD-type displays are known to employ response time compensation for video playback. Without response time compensation, the video image observed by the human eye becomes blurred, distorted or choppy because the amount of time taken to display an entire frame of video exceeds the amount of time which the display must be refreshed with a new graphic, or new frame. Response time compensation is therefore used in LCD-type displays in order to avoid perception by the human eye.
Typically, response time compensation techniques for video playback on LCD-type displays operate on the rasterizing engine, and therefore have no mechanism for indicating a pause, stop, single-step, or slow-motion rendering of video. As a result, when response time compensation techniques for video playback on LCD-type displays are used, artifacts, aberrations or other types of distortions are displayed during the video stop, pause, single-step or slow-motion modes.
Various other types of filtering techniques facilitate the playback of motion video. For example, other types of filtering used during motion video may include deinterlacing, denoising and other types of temporal filters. However, when motion video is paused, or when a still image is displayed, the filtering techniques may also cause aberrations, due to these compensation techniques.